tests : fix compile warning

tests/test-quantize-fns.cpp

@@ -79,9 +79,9 @@ static float dot_product(const float * a1, const float * a2, size_t test_size) {
 }
 
 // Total dot product error
-static float dot_product_error(
-    const ggml_type_traits * qfns, const ggml_type_traits_cpu * qfns_cpu, size_t test_size, const float * test_data1, const float *test_data2
-) {
+static float dot_product_error(const ggml_type_traits * qfns, const ggml_type_traits_cpu * qfns_cpu, size_t test_size, const float * test_data1, const float * test_data2) {
+    GGML_UNUSED(qfns);
+
     std::vector<uint8_t> tmp_q1(2*test_size);
     std::vector<uint8_t> tmp_q2(2*test_size);